//--------------------------------------------------------------------------------------
// File: DDSTextureLoader.cpp
//
// Function for loading a DDS texture and creating a Direct3D 11 runtime resource for it
//
// Note this function is useful as a light-weight runtime loader for DDS files. For
// a full-featured DDS file reader, writer, and texture processing pipeline see
// the 'Texconv' sample and the 'DirectXTex' library.
//
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
// PARTICULAR PURPOSE.
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//--------------------------------------------------------------------------------------

#include "BasePCH.h"
#include "DDSTextureLoader.h"
//#include "pch.h"
#include <dxgiformat.h>
#include <assert.h>
#include <memory>
#include <algorithm>
//#include "DirectXSample.h"

#ifdef CORE_API_DX11

//using namespace Microsoft::WRL;

//--------------------------------------------------------------------------------------
// Macros
//--------------------------------------------------------------------------------------
#ifndef MAKEFOURCC
#define MAKEFOURCC(ch0, ch1, ch2, ch3)                              \
                ((TU32)(byte)(ch0) | ((TU32)(byte)(ch1) << 8) |       \
                ((TU32)(byte)(ch2) << 16) | ((TU32)(byte)(ch3) << 24))
#endif /* defined(MAKEFOURCC) */

//--------------------------------------------------------------------------------------
// DDS file structure definitions
//
// See DDS.h in the 'Texconv' sample and the 'DirectXTex' library
//--------------------------------------------------------------------------------------
#pragma pack(push, 1)

#define DDS_MAGIC 0x20534444 // "DDS "

struct DDS_PIXELFORMAT
{
	TU32  size;
	TU32  flags;
	TU32  fourCC;
	TU32  RGBBitCount;
	TU32  RBitMask;
	TU32  GBitMask;
	TU32  BBitMask;
	TU32  ABitMask;
};

#define DDS_FOURCC      0x00000004  // DDPF_FOURCC
#define DDS_RGB         0x00000040  // DDPF_RGB
#define DDS_RGBA        0x00000041  // DDPF_RGB | DDPF_ALPHAPIXELS
#define DDS_LUMINANCE   0x00020000  // DDPF_LUMINANCE
#define DDS_LUMINANCEA  0x00020001  // DDPF_LUMINANCE | DDPF_ALPHAPIXELS
#define DDS_ALPHA       0x00000002  // DDPF_ALPHA
#define DDS_PAL8        0x00000020  // DDPF_PALETTEINDEXED8

#define DDS_HEADER_FLAGS_TEXTURE        0x00001007  // DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH | DDSD_PIXELFORMAT
#define DDS_HEADER_FLAGS_MIPMAP         0x00020000  // DDSD_MIPMAPCOUNT
#define DDS_HEADER_FLAGS_VOLUME         0x00800000  // DDSD_DEPTH
#define DDS_HEADER_FLAGS_PITCH          0x00000008  // DDSD_PITCH
#define DDS_HEADER_FLAGS_LINEARSIZE     0x00080000  // DDSD_LINEARSIZE

#define DDS_HEIGHT 0x00000002 // DDSD_HEIGHT
#define DDS_WIDTH  0x00000004 // DDSD_WIDTH

#define DDS_SURFACE_FLAGS_TEXTURE 0x00001000 // DDSCAPS_TEXTURE
#define DDS_SURFACE_FLAGS_MIPMAP  0x00400008 // DDSCAPS_COMPLEX | DDSCAPS_MIPMAP
#define DDS_SURFACE_FLAGS_CUBEMAP 0x00000008 // DDSCAPS_COMPLEX

#define DDS_CUBEMAP_POSITIVEX 0x00000600 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_POSITIVEX
#define DDS_CUBEMAP_NEGATIVEX 0x00000a00 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_NEGATIVEX
#define DDS_CUBEMAP_POSITIVEY 0x00001200 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_POSITIVEY
#define DDS_CUBEMAP_NEGATIVEY 0x00002200 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_NEGATIVEY
#define DDS_CUBEMAP_POSITIVEZ 0x00004200 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_POSITIVEZ
#define DDS_CUBEMAP_NEGATIVEZ 0x00008200 // DDSCAPS2_CUBEMAP | DDSCAPS2_CUBEMAP_NEGATIVEZ

#define DDS_CUBEMAP_ALLFACES (DDS_CUBEMAP_POSITIVEX | DDS_CUBEMAP_NEGATIVEX |\
                              DDS_CUBEMAP_POSITIVEY | DDS_CUBEMAP_NEGATIVEY |\
                              DDS_CUBEMAP_POSITIVEZ | DDS_CUBEMAP_NEGATIVEZ)

#define DDS_CUBEMAP 0x00000200 // DDSCAPS2_CUBEMAP

#define DDS_FLAGS_VOLUME 0x00200000 // DDSCAPS2_VOLUME

typedef struct
{
	TU32          size;
	TU32          flags;
	TU32          height;
	TU32          width;
	TU32          pitchOrLinearSize;
	TU32          depth; // only if DDS_HEADER_FLAGS_VOLUME is set in flags
	TU32          mipMapCount;
	TU32          reserved1[11];
	DDS_PIXELFORMAT ddspf;
	TU32          caps;
	TU32          caps2;
	TU32          caps3;
	TU32          caps4;
	TU32          reserved2;
} DDS_HEADER;

typedef struct
{
	DXGI_FORMAT dxgiFormat;
	TU32      resourceDimension;
	TU32      miscFlag; // see D3D11_RESOURCE_MISC_FLAG
	TU32      arraySize;
	TU32      reserved;
} DDS_HEADER_DXT10;

#pragma pack(pop)

//--------------------------------------------------------------------------------------
// Return the BPP for a particular format
//--------------------------------------------------------------------------------------
static size_t BitsPerPixel(_In_ DXGI_FORMAT fmt)
{
	switch (fmt)
	{
		case DXGI_FORMAT_R32G32B32A32_TYPELESS:
		case DXGI_FORMAT_R32G32B32A32_FLOAT:
		case DXGI_FORMAT_R32G32B32A32_UINT:
		case DXGI_FORMAT_R32G32B32A32_SINT:
			return 128;

		case DXGI_FORMAT_R32G32B32_TYPELESS:
		case DXGI_FORMAT_R32G32B32_FLOAT:
		case DXGI_FORMAT_R32G32B32_UINT:
		case DXGI_FORMAT_R32G32B32_SINT:
			return 96;

		case DXGI_FORMAT_R16G16B16A16_TYPELESS:
		case DXGI_FORMAT_R16G16B16A16_FLOAT:
		case DXGI_FORMAT_R16G16B16A16_UNORM:
		case DXGI_FORMAT_R16G16B16A16_UINT:
		case DXGI_FORMAT_R16G16B16A16_SNORM:
		case DXGI_FORMAT_R16G16B16A16_SINT:
		case DXGI_FORMAT_R32G32_TYPELESS:
		case DXGI_FORMAT_R32G32_FLOAT:
		case DXGI_FORMAT_R32G32_UINT:
		case DXGI_FORMAT_R32G32_SINT:
		case DXGI_FORMAT_R32G8X24_TYPELESS:
		case DXGI_FORMAT_D32_FLOAT_S8X24_UINT:
		case DXGI_FORMAT_R32_FLOAT_X8X24_TYPELESS:
		case DXGI_FORMAT_X32_TYPELESS_G8X24_UINT:
			return 64;

		case DXGI_FORMAT_R10G10B10A2_TYPELESS:
		case DXGI_FORMAT_R10G10B10A2_UNORM:
		case DXGI_FORMAT_R10G10B10A2_UINT:
		case DXGI_FORMAT_R11G11B10_FLOAT:
		case DXGI_FORMAT_R8G8B8A8_TYPELESS:
		case DXGI_FORMAT_R8G8B8A8_UNORM:
		case DXGI_FORMAT_R8G8B8A8_UNORM_SRGB:
		case DXGI_FORMAT_R8G8B8A8_UINT:
		case DXGI_FORMAT_R8G8B8A8_SNORM:
		case DXGI_FORMAT_R8G8B8A8_SINT:
		case DXGI_FORMAT_R16G16_TYPELESS:
		case DXGI_FORMAT_R16G16_FLOAT:
		case DXGI_FORMAT_R16G16_UNORM:
		case DXGI_FORMAT_R16G16_UINT:
		case DXGI_FORMAT_R16G16_SNORM:
		case DXGI_FORMAT_R16G16_SINT:
		case DXGI_FORMAT_R32_TYPELESS:
		case DXGI_FORMAT_D32_FLOAT:
		case DXGI_FORMAT_R32_FLOAT:
		case DXGI_FORMAT_R32_UINT:
		case DXGI_FORMAT_R32_SINT:
		case DXGI_FORMAT_R24G8_TYPELESS:
		case DXGI_FORMAT_D24_UNORM_S8_UINT:
		case DXGI_FORMAT_R24_UNORM_X8_TYPELESS:
		case DXGI_FORMAT_X24_TYPELESS_G8_UINT:
		case DXGI_FORMAT_R9G9B9E5_SHAREDEXP:
		case DXGI_FORMAT_R8G8_B8G8_UNORM:
		case DXGI_FORMAT_G8R8_G8B8_UNORM:
		case DXGI_FORMAT_B8G8R8A8_UNORM:
		case DXGI_FORMAT_B8G8R8X8_UNORM:
		case DXGI_FORMAT_R10G10B10_XR_BIAS_A2_UNORM:
		case DXGI_FORMAT_B8G8R8A8_TYPELESS:
		case DXGI_FORMAT_B8G8R8A8_UNORM_SRGB:
		case DXGI_FORMAT_B8G8R8X8_TYPELESS:
		case DXGI_FORMAT_B8G8R8X8_UNORM_SRGB:
			return 32;

		case DXGI_FORMAT_R8G8_TYPELESS:
		case DXGI_FORMAT_R8G8_UNORM:
		case DXGI_FORMAT_R8G8_UINT:
		case DXGI_FORMAT_R8G8_SNORM:
		case DXGI_FORMAT_R8G8_SINT:
		case DXGI_FORMAT_R16_TYPELESS:
		case DXGI_FORMAT_R16_FLOAT:
		case DXGI_FORMAT_D16_UNORM:
		case DXGI_FORMAT_R16_UNORM:
		case DXGI_FORMAT_R16_UINT:
		case DXGI_FORMAT_R16_SNORM:
		case DXGI_FORMAT_R16_SINT:
		case DXGI_FORMAT_B5G6R5_UNORM:
		case DXGI_FORMAT_B5G5R5A1_UNORM:
		case DXGI_FORMAT_B4G4R4A4_UNORM:
			return 16;

		case DXGI_FORMAT_R8_TYPELESS:
		case DXGI_FORMAT_R8_UNORM:
		case DXGI_FORMAT_R8_UINT:
		case DXGI_FORMAT_R8_SNORM:
		case DXGI_FORMAT_R8_SINT:
		case DXGI_FORMAT_A8_UNORM:
			return 8;

		case DXGI_FORMAT_R1_UNORM:
			return 1;

		case DXGI_FORMAT_BC1_TYPELESS:
		case DXGI_FORMAT_BC1_UNORM:
		case DXGI_FORMAT_BC1_UNORM_SRGB:
		case DXGI_FORMAT_BC4_TYPELESS:
		case DXGI_FORMAT_BC4_UNORM:
		case DXGI_FORMAT_BC4_SNORM:
			return 4;

		case DXGI_FORMAT_BC2_TYPELESS:
		case DXGI_FORMAT_BC2_UNORM:
		case DXGI_FORMAT_BC2_UNORM_SRGB:
		case DXGI_FORMAT_BC3_TYPELESS:
		case DXGI_FORMAT_BC3_UNORM:
		case DXGI_FORMAT_BC3_UNORM_SRGB:
		case DXGI_FORMAT_BC5_TYPELESS:
		case DXGI_FORMAT_BC5_UNORM:
		case DXGI_FORMAT_BC5_SNORM:
		case DXGI_FORMAT_BC6H_TYPELESS:
		case DXGI_FORMAT_BC6H_UF16:
		case DXGI_FORMAT_BC6H_SF16:
		case DXGI_FORMAT_BC7_TYPELESS:
		case DXGI_FORMAT_BC7_UNORM:
		case DXGI_FORMAT_BC7_UNORM_SRGB:
			return 8;

		default:
			return 0;
	}
}


//--------------------------------------------------------------------------------------
// Get surface information for a particular format
//--------------------------------------------------------------------------------------
static void GetSurfaceInfo(
	_In_ size_t width,
	_In_ size_t height,
	_In_ DXGI_FORMAT fmt,
	_Out_opt_ size_t* outNumBytes,
	_Out_opt_ size_t* outRowBytes,
	_Out_opt_ size_t* outNumRows
	)
{
	size_t numBytes = 0;
	size_t rowBytes = 0;
	size_t numRows = 0;

	bool bc = false;
	bool packed = false;
	size_t bcnumBytesPerBlock = 0;
	switch (fmt)
	{
		case DXGI_FORMAT_BC1_TYPELESS:
		case DXGI_FORMAT_BC1_UNORM:
		case DXGI_FORMAT_BC1_UNORM_SRGB:
		case DXGI_FORMAT_BC4_TYPELESS:
		case DXGI_FORMAT_BC4_UNORM:
		case DXGI_FORMAT_BC4_SNORM:
			bc = true;
			bcnumBytesPerBlock = 8;
			break;

		case DXGI_FORMAT_BC2_TYPELESS:
		case DXGI_FORMAT_BC2_UNORM:
		case DXGI_FORMAT_BC2_UNORM_SRGB:
		case DXGI_FORMAT_BC3_TYPELESS:
		case DXGI_FORMAT_BC3_UNORM:
		case DXGI_FORMAT_BC3_UNORM_SRGB:
		case DXGI_FORMAT_BC5_TYPELESS:
		case DXGI_FORMAT_BC5_UNORM:
		case DXGI_FORMAT_BC5_SNORM:
		case DXGI_FORMAT_BC6H_TYPELESS:
		case DXGI_FORMAT_BC6H_UF16:
		case DXGI_FORMAT_BC6H_SF16:
		case DXGI_FORMAT_BC7_TYPELESS:
		case DXGI_FORMAT_BC7_UNORM:
		case DXGI_FORMAT_BC7_UNORM_SRGB:
			bc = true;
			bcnumBytesPerBlock = 16;
			break;

		case DXGI_FORMAT_R8G8_B8G8_UNORM:
		case DXGI_FORMAT_G8R8_G8B8_UNORM:
			packed = true;
			break;
	}

	if (bc)
	{
		size_t numBlocksWide = 0;
		if (width > 0)
		{
			numBlocksWide = std::max<size_t>(1, (width + 3) / 4);
		}
		size_t numBlocksHigh = 0;
		if (height > 0)
		{
			numBlocksHigh = std::max<size_t>(1, (height + 3) / 4);
		}
		rowBytes = numBlocksWide * bcnumBytesPerBlock;
		numRows = numBlocksHigh;
	}
	else if (packed)
	{
		rowBytes = ((width + 1) >> 1) * 4;
		numRows = height;
	}
	else
	{
		size_t bpp = BitsPerPixel(fmt);
		rowBytes = (width * bpp + 7) / 8; // round up to nearest byte
		numRows = height;
	}

	numBytes = rowBytes * numRows;
	if (outNumBytes)
	{
		*outNumBytes = numBytes;
	}
	if (outRowBytes)
	{
		*outRowBytes = rowBytes;
	}
	if (outNumRows)
	{
		*outNumRows = numRows;
	}
}


//--------------------------------------------------------------------------------------
#define ISBITMASK(r, g, b, a) (ddpf.RBitMask == r && ddpf.GBitMask == g && ddpf.BBitMask == b && ddpf.ABitMask == a)

static DXGI_FORMAT GetDXGIFormat(const DDS_PIXELFORMAT& ddpf)
{
	if (ddpf.flags & DDS_RGB)
	{
		// Note that sRGB formats are written using the "DX10" extended header

		switch (ddpf.RGBBitCount)
		{
			case 32:
				if (ISBITMASK(0x000000ff, 0x0000ff00, 0x00ff0000, 0xff000000))
				{
					return DXGI_FORMAT_R8G8B8A8_UNORM;
				}

				if (ISBITMASK(0x00ff0000, 0x0000ff00, 0x000000ff, 0xff000000))
				{
					return DXGI_FORMAT_B8G8R8A8_UNORM;
				}

				if (ISBITMASK(0x00ff0000, 0x0000ff00, 0x000000ff, 0x00000000))
				{
					return DXGI_FORMAT_B8G8R8X8_UNORM;
				}

				// No DXGI format maps to ISBITMASK(0x000000ff, 0x0000ff00, 0x00ff0000, 0x00000000) aka D3DFMT_X8B8G8R8

				// Note that many common DDS reader/writers (including D3DX) swap the
				// the RED/BLUE masks for 10:10:10:2 formats. We assumme
				// below that the 'backwards' header mask is being used since it is most
				// likely written by D3DX. The more robust solution is to use the 'DX10'
				// header extension and specify the DXGI_FORMAT_R10G10B10A2_UNORM format directly

				// For 'correct' writers, this should be 0x000003ff, 0x000ffc00, 0x3ff00000 for RGB data
				if (ISBITMASK(0x3ff00000, 0x000ffc00, 0x000003ff, 0xc0000000))
				{
					return DXGI_FORMAT_R10G10B10A2_UNORM;
				}

				// No DXGI format maps to ISBITMASK(0x000003ff, 0x000ffc00, 0x3ff00000, 0xc0000000) aka D3DFMT_A2R10G10B10

				if (ISBITMASK(0x0000ffff, 0xffff0000, 0x00000000, 0x00000000))
				{
					return DXGI_FORMAT_R16G16_UNORM;
				}

				if (ISBITMASK(0xffffffff, 0x00000000, 0x00000000, 0x00000000))
				{
					// Only 32-bit color channel format in D3D9 was R32F
					return DXGI_FORMAT_R32_FLOAT; // D3DX writes this out as a FourCC of 114
				}
				break;

			case 24:
				// No 24bpp DXGI formats aka D3DFMT_R8G8B8
				break;

			case 16:
				if (ISBITMASK(0x7c00, 0x03e0, 0x001f, 0x8000))
				{
					return DXGI_FORMAT_B5G5R5A1_UNORM;
				}
				if (ISBITMASK(0xf800, 0x07e0, 0x001f, 0x0000))
				{
					return DXGI_FORMAT_B5G6R5_UNORM;
				}

				// No DXGI format maps to ISBITMASK(0x7c00, 0x03e0, 0x001f, 0x0000) aka D3DFMT_X1R5G5B5
				if (ISBITMASK(0x0f00, 0x00f0, 0x000f, 0xf000))
				{
					return DXGI_FORMAT_B4G4R4A4_UNORM;
				}

				// No DXGI format maps to ISBITMASK(0x0f00, 0x00f0, 0x000f, 0x0000) aka D3DFMT_X4R4G4B4

				// No 3:3:2, 3:3:2:8, or paletted DXGI formats aka D3DFMT_A8R3G3B2, D3DFMT_R3G3B2, D3DFMT_P8, D3DFMT_A8P8, etc.
				break;
		}
	}
	else if (ddpf.flags & DDS_LUMINANCE)
	{
		if (8 == ddpf.RGBBitCount)
		{
			if (ISBITMASK(0x000000ff, 0x00000000, 0x00000000, 0x00000000))
			{
				return DXGI_FORMAT_R8_UNORM; // D3DX10/11 writes this out as DX10 extension
			}

			// No DXGI format maps to ISBITMASK(0x0f, 0x00, 0x00, 0xf0) aka D3DFMT_A4L4
		}

		if (16 == ddpf.RGBBitCount)
		{
			if (ISBITMASK(0x0000ffff, 0x00000000, 0x00000000, 0x00000000))
			{
				return DXGI_FORMAT_R16_UNORM; // D3DX10/11 writes this out as DX10 extension
			}
			if (ISBITMASK(0x000000ff, 0x00000000, 0x00000000, 0x0000ff00))
			{
				return DXGI_FORMAT_R8G8_UNORM; // D3DX10/11 writes this out as DX10 extension
			}
		}
	}
	else if (ddpf.flags & DDS_ALPHA)
	{
		if (8 == ddpf.RGBBitCount)
		{
			return DXGI_FORMAT_A8_UNORM;
		}
	}
	else if (ddpf.flags & DDS_FOURCC)
	{
		if (MAKEFOURCC('D', 'X', 'T', '1') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC1_UNORM;
		}
		if (MAKEFOURCC('D', 'X', 'T', '3') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC2_UNORM;
		}
		if (MAKEFOURCC('D', 'X', 'T', '5') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC3_UNORM;
		}

		// While pre-mulitplied alpha isn't directly supported by the DXGI formats,
		// they are basically the same as these BC formats so they can be mapped
		if (MAKEFOURCC('D', 'X', 'T', '2') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC2_UNORM;
		}
		if (MAKEFOURCC('D', 'X', 'T', '4') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC3_UNORM;
		}

		if (MAKEFOURCC('A', 'T', 'I', '1') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC4_UNORM;
		}
		if (MAKEFOURCC('B', 'C', '4', 'U') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC4_UNORM;
		}
		if (MAKEFOURCC('B', 'C', '4', 'S') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC4_SNORM;
		}

		if (MAKEFOURCC('A', 'T', 'I', '2') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC5_UNORM;
		}
		if (MAKEFOURCC('B', 'C', '5', 'U') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC5_UNORM;
		}
		if (MAKEFOURCC('B', 'C', '5', 'S') == ddpf.fourCC)
		{
			return DXGI_FORMAT_BC5_SNORM;
		}

		// BC6H and BC7 are written using the "DX10" extended header

		if (MAKEFOURCC('R', 'G', 'B', 'G') == ddpf.fourCC)
		{
			return DXGI_FORMAT_R8G8_B8G8_UNORM;
		}
		if (MAKEFOURCC('G', 'R', 'G', 'B') == ddpf.fourCC)
		{
			return DXGI_FORMAT_G8R8_G8B8_UNORM;
		}

		// Check for D3DFORMAT enums being set here
		switch (ddpf.fourCC)
		{
			case 36: // D3DFMT_A16B16G16R16
				return DXGI_FORMAT_R16G16B16A16_UNORM;

			case 110: // D3DFMT_Q16W16V16U16
				return DXGI_FORMAT_R16G16B16A16_SNORM;

			case 111: // D3DFMT_R16F
				return DXGI_FORMAT_R16_FLOAT;

			case 112: // D3DFMT_G16R16F
				return DXGI_FORMAT_R16G16_FLOAT;

			case 113: // D3DFMT_A16B16G16R16F
				return DXGI_FORMAT_R16G16B16A16_FLOAT;

			case 114: // D3DFMT_R32F
				return DXGI_FORMAT_R32_FLOAT;

			case 115: // D3DFMT_G32R32F
				return DXGI_FORMAT_R32G32_FLOAT;

			case 116: // D3DFMT_A32B32G32R32F
				return DXGI_FORMAT_R32G32B32A32_FLOAT;
		}
	}

	return DXGI_FORMAT_UNKNOWN;
}


//--------------------------------------------------------------------------------------
static TBOOL FillInitData(
	_In_ size_t width,
	_In_ size_t height,
	_In_ size_t depth,
	_In_ size_t mipCount,
	_In_ size_t arraySize,
	_In_ DXGI_FORMAT format,
	_In_ size_t maxsize,
	_In_ size_t bitSize,
	_In_reads_bytes_(bitSize) const byte* bitData,
	_Out_ size_t& twidth,
	_Out_ size_t& theight,
	_Out_ size_t& tdepth,
	_Out_ size_t& skipMip,
	_Out_writes_(mipCount*arraySize) D3D11_SUBRESOURCE_DATA* initData
	)
{
	if (!bitData || !initData) return false;

	skipMip = 0;
	twidth = 0;
	theight = 0;
	tdepth = 0;

	size_t NumBytes = 0;
	size_t RowBytes = 0;
	size_t NumRows = 0;
	const byte* pSrcBits = bitData;
	const byte* pEndBits = bitData + bitSize;

	size_t index = 0;
	for (size_t j = 0; j < arraySize; j++)
	{
		size_t w = width;
		size_t h = height;
		size_t d = depth;
		for (size_t i = 0; i < mipCount; i++)
		{
			GetSurfaceInfo(w, h, format, &NumBytes, &RowBytes, &NumRows);

			if ((mipCount <= 1) || !maxsize || (w <= maxsize && h <= maxsize && d <= maxsize))
			{
				if (!twidth)
				{
					twidth = w;
					theight = h;
					tdepth = d;
				}

				initData[index].pSysMem = (const void*)pSrcBits;
				initData[index].SysMemPitch = static_cast<UINT>(RowBytes);
				initData[index].SysMemSlicePitch = static_cast<UINT>(NumBytes);
				++index;
			}
			else
			{
				++skipMip;
			}

			if (pSrcBits + (NumBytes*d) > pEndBits) return false;

			pSrcBits += NumBytes * d;

			w = w >> 1;
			h = h >> 1;
			d = d >> 1;
			if (w == 0)
			{
				w = 1;
			}
			if (h == 0)
			{
				h = 1;
			}
			if (d == 0)
			{
				d = 1;
			}
		}
	}

	if (!index) return false;
	return true;
}


//--------------------------------------------------------------------------------------
static HRESULT CreateD3DResources(
	_In_ ID3D11Device* d3dDevice,
	_In_ TU32 resDim,
	_In_ size_t width,
	_In_ size_t height,
	_In_ size_t depth,
	_In_ size_t mipCount,
	_In_ size_t arraySize,
	_In_ DXGI_FORMAT format,
	_In_ bool isCubeMap,
	_In_reads_(mipCount*arraySize) D3D11_SUBRESOURCE_DATA* initData,
	_Out_opt_ ID3D11Resource** texture,
	_Out_opt_ ID3D11ShaderResourceView** textureView
	)
{
	if (!d3dDevice || !initData)
	{
		return E_INVALIDARG;
	}

	HRESULT hr = E_FAIL;

	switch (resDim)
	{
		case D3D11_RESOURCE_DIMENSION_TEXTURE1D:
		{
			D3D11_TEXTURE1D_DESC desc;
			desc.Width = static_cast<UINT>(width);
			desc.MipLevels = static_cast<UINT>(mipCount);
			desc.ArraySize = static_cast<UINT>(arraySize);
			desc.Format = format;
			desc.Usage = D3D11_USAGE_DEFAULT;
			desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
			desc.CPUAccessFlags = 0;
			desc.MiscFlags = 0;

			ID3D11Texture1D* tex = nullptr;
			hr = d3dDevice->CreateTexture1D(&desc, initData, &tex);

			if (SUCCEEDED(hr) && tex != 0)
			{
				if (textureView != 0)
				{
					D3D11_SHADER_RESOURCE_VIEW_DESC SRVDesc;
					memset(&SRVDesc, 0, sizeof(SRVDesc));
					SRVDesc.Format = format;

					if (arraySize > 1)
					{
						SRVDesc.ViewDimension = D3D_SRV_DIMENSION_TEXTURE1DARRAY;
						SRVDesc.Texture1DArray.MipLevels = desc.MipLevels;
						SRVDesc.Texture1DArray.ArraySize = static_cast<UINT>(arraySize);
					}
					else
					{
						SRVDesc.ViewDimension = D3D_SRV_DIMENSION_TEXTURE1D;
						SRVDesc.Texture1D.MipLevels = desc.MipLevels;
					}

					hr = d3dDevice->CreateShaderResourceView(tex, &SRVDesc, textureView);

					if (FAILED(hr))
					{
						tex->Release();
						return hr;
					}
				}

				if (texture != 0)
				{
					*texture = tex;
				}
				else
				{
					tex->Release();
				}
			}
		}
		break;

		case D3D11_RESOURCE_DIMENSION_TEXTURE2D:
		{
			D3D11_TEXTURE2D_DESC desc;
			desc.Width = static_cast<UINT>(width);
			desc.Height = static_cast<UINT>(height);
			desc.MipLevels = static_cast<UINT>(mipCount);
			desc.ArraySize = static_cast<UINT>(arraySize);
			desc.Format = format;
			desc.SampleDesc.Count = 1;
			desc.SampleDesc.Quality = 0;
			desc.Usage = D3D11_USAGE_DEFAULT;
			desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
			desc.CPUAccessFlags = 0;
			desc.MiscFlags = (isCubeMap) ? D3D11_RESOURCE_MISC_TEXTURECUBE : 0;

			ID3D11Texture2D* tex = nullptr;
			hr = d3dDevice->CreateTexture2D(&desc, initData, &tex);

			if (SUCCEEDED(hr) && tex != 0)
			{
				if (textureView != 0)
				{
					D3D11_SHADER_RESOURCE_VIEW_DESC SRVDesc;
					memset(&SRVDesc, 0, sizeof(SRVDesc));
					SRVDesc.Format = format;

					if (isCubeMap)
					{
						if (arraySize > 6)
						{
							SRVDesc.ViewDimension = D3D_SRV_DIMENSION_TEXTURECUBEARRAY;
							SRVDesc.TextureCubeArray.MipLevels = desc.MipLevels;

							// Earlier we set arraySize to (NumCubes * 6)
							SRVDesc.TextureCubeArray.NumCubes = static_cast<UINT>(arraySize / 6);
						}
						else
						{
							SRVDesc.ViewDimension = D3D_SRV_DIMENSION_TEXTURECUBE;
							SRVDesc.TextureCube.MipLevels = desc.MipLevels;
						}
					}
					else if (arraySize > 1)
					{
						SRVDesc.ViewDimension = D3D_SRV_DIMENSION_TEXTURE2DARRAY;
						SRVDesc.Texture2DArray.MipLevels = desc.MipLevels;
						SRVDesc.Texture2DArray.ArraySize = static_cast<UINT>(arraySize);
					}
					else
					{
						SRVDesc.ViewDimension = D3D_SRV_DIMENSION_TEXTURE2D;
						SRVDesc.Texture2D.MipLevels = desc.MipLevels;
					}

					hr = d3dDevice->CreateShaderResourceView(tex, &SRVDesc, textureView);

					if (FAILED(hr))
					{
						tex->Release();
						return hr;
					}
				}

				if (texture != 0)
				{
					*texture = tex;
				}
				else
				{
					tex->Release();
				}
			}
		}
		break;

		case D3D11_RESOURCE_DIMENSION_TEXTURE3D:
		{
			D3D11_TEXTURE3D_DESC desc;
			desc.Width = static_cast<UINT>(width);
			desc.Height = static_cast<UINT>(height);
			desc.Depth = static_cast<UINT>(depth);
			desc.MipLevels = static_cast<UINT>(mipCount);
			desc.Format = format;
			desc.Usage = D3D11_USAGE_DEFAULT;
			desc.BindFlags = D3D11_BIND_SHADER_RESOURCE;
			desc.CPUAccessFlags = 0;
			desc.MiscFlags = 0;

			ID3D11Texture3D* tex = nullptr;
			hr = d3dDevice->CreateTexture3D(&desc, initData, &tex);

			if (SUCCEEDED(hr) && tex != 0)
			{
				if (textureView != 0)
				{
					D3D11_SHADER_RESOURCE_VIEW_DESC SRVDesc;
					memset(&SRVDesc, 0, sizeof(SRVDesc));
					SRVDesc.Format = format;
					SRVDesc.ViewDimension = D3D_SRV_DIMENSION_TEXTURE3D;
					SRVDesc.Texture3D.MipLevels = desc.MipLevels;

					hr = d3dDevice->CreateShaderResourceView(tex, &SRVDesc, textureView);

					if (FAILED(hr))
					{
						tex->Release();
						return hr;
					}
				}

				if (texture != 0)
				{
					*texture = tex;
				}
				else
				{
					tex->Release();
				}
			}
		}
		break;
	}

	return hr;
}


//--------------------------------------------------------------------------------------
static TBOOL CreateTextureFromDDS(
	_In_ ID3D11Device* d3dDevice,
	_In_ const DDS_HEADER* header,
	_In_reads_bytes_(bitSize) const byte* bitData,
	_In_ size_t bitSize,
	_Out_opt_ ID3D11Resource** texture,
	_Out_opt_ ID3D11ShaderResourceView** textureView,
	_In_ size_t maxsize
	)
{
	HRESULT hr = S_OK;

	size_t width = header->width;
	size_t height = header->height;
	size_t depth = header->depth;

	TU32 resDim = D3D11_RESOURCE_DIMENSION_UNKNOWN;
	size_t arraySize = 1;
	DXGI_FORMAT format = DXGI_FORMAT_UNKNOWN;
	bool isCubeMap = false;

	size_t mipCount = header->mipMapCount;
	if (0 == mipCount)
	{
		mipCount = 1;
	}

	if ((header->ddspf.flags & DDS_FOURCC) &&
		(MAKEFOURCC('D', 'X', '1', '0') == header->ddspf.fourCC))
	{
		const DDS_HEADER_DXT10* d3d10ext = reinterpret_cast<const DDS_HEADER_DXT10*>((const char*)header + sizeof(DDS_HEADER));

		arraySize = d3d10ext->arraySize;
		if (arraySize == 0) return false;
		if (BitsPerPixel(d3d10ext->dxgiFormat) == 0) return false;

		format = d3d10ext->dxgiFormat;

		switch (d3d10ext->resourceDimension)
		{
			case D3D11_RESOURCE_DIMENSION_TEXTURE1D:
				// D3DX writes 1D textures with a fixed Height of 1
				if ((header->flags & DDS_HEIGHT) && height != 1)  return false;
				height = depth = 1;
				break;

			case D3D11_RESOURCE_DIMENSION_TEXTURE2D:
				if (d3d10ext->miscFlag & D3D11_RESOURCE_MISC_TEXTURECUBE)
				{
					arraySize *= 6;
					isCubeMap = true;
				}
				depth = 1;
				break;

			case D3D11_RESOURCE_DIMENSION_TEXTURE3D:
				if (!(header->flags & DDS_HEADER_FLAGS_VOLUME))  return false;
				if (arraySize > 1)  return false;
				break;

			default:
				return false;
		}

		resDim = d3d10ext->resourceDimension;
	}
	else
	{
		format = GetDXGIFormat(header->ddspf);

		if (format == DXGI_FORMAT_UNKNOWN)
		{
			return false;
		}

		if (header->flags & DDS_HEADER_FLAGS_VOLUME)
		{
			resDim = D3D11_RESOURCE_DIMENSION_TEXTURE3D;
		}
		else
		{
			if (header->caps2 & DDS_CUBEMAP)
			{
				// We require all six faces to be defined
				if ((header->caps2 & DDS_CUBEMAP_ALLFACES) != DDS_CUBEMAP_ALLFACES)
				{
					return false;
				}

				arraySize = 6;
				isCubeMap = true;
			}

			depth = 1;
			resDim = D3D11_RESOURCE_DIMENSION_TEXTURE2D;

			// Note there's no way for a legacy Direct3D 9 DDS to express a '1D' texture
		}

		assert(BitsPerPixel(format) != 0);
	}

	// Bound sizes (for security purposes we don't trust DDS file metadata larger than the D3D 11.x hardware requirements)
	if (mipCount > D3D11_REQ_MIP_LEVELS)
	{
		return false;
	}

	switch (resDim)
	{
		case D3D11_RESOURCE_DIMENSION_TEXTURE1D:
			if ((arraySize > D3D11_REQ_TEXTURE1D_ARRAY_AXIS_DIMENSION) ||
				(width > D3D11_REQ_TEXTURE1D_U_DIMENSION))
			{
				return false;
			}
			break;

		case D3D11_RESOURCE_DIMENSION_TEXTURE2D:
			if (isCubeMap)
			{
				// This is the right bound because we set arraySize to (NumCubes*6) above
				if ((arraySize > D3D11_REQ_TEXTURE2D_ARRAY_AXIS_DIMENSION) ||
					(width > D3D11_REQ_TEXTURECUBE_DIMENSION) ||
					(height > D3D11_REQ_TEXTURECUBE_DIMENSION))
				{
					return false;
				}
			}
			else if ((arraySize > D3D11_REQ_TEXTURE2D_ARRAY_AXIS_DIMENSION) ||
					 (width > D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION) ||
					 (height > D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION))
			{
				return false;
			}
			break;

		case D3D11_RESOURCE_DIMENSION_TEXTURE3D:
			if ((arraySize > 1) ||
				(width > D3D11_REQ_TEXTURE3D_U_V_OR_W_DIMENSION) ||
				(height > D3D11_REQ_TEXTURE3D_U_V_OR_W_DIMENSION) ||
				(depth > D3D11_REQ_TEXTURE3D_U_V_OR_W_DIMENSION))
			{
				return false;
			}
			break;
	}

	// Create the texture
	std::unique_ptr<D3D11_SUBRESOURCE_DATA> initData(new D3D11_SUBRESOURCE_DATA[mipCount * arraySize]);

	size_t skipMip = 0;
	size_t twidth = 0;
	size_t theight = 0;
	size_t tdepth = 0;
	if (!FillInitData(width, height, depth, mipCount, arraySize, format, maxsize, bitSize, bitData, twidth, theight, tdepth, skipMip, initData.get())) return false;

	hr = CreateD3DResources(d3dDevice, resDim, twidth, theight, tdepth, mipCount - skipMip, arraySize, format, isCubeMap, initData.get(), texture, textureView);

	if (FAILED(hr) && !maxsize && (mipCount > 1))
	{
		// Retry with a maxsize determined by feature level
		switch (d3dDevice->GetFeatureLevel())
		{
			case D3D_FEATURE_LEVEL_9_1:
			case D3D_FEATURE_LEVEL_9_2:
				if (isCubeMap)
				{
					maxsize = D3D_FL9_1_REQ_TEXTURECUBE_DIMENSION;
				}
				else
				{
					maxsize = (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE3D)
						? D3D_FL9_1_REQ_TEXTURE3D_U_V_OR_W_DIMENSION
						: D3D_FL9_1_REQ_TEXTURE2D_U_OR_V_DIMENSION;
				}
				break;

			case D3D_FEATURE_LEVEL_9_3:
				maxsize = (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE3D)
					? D3D_FL9_1_REQ_TEXTURE3D_U_V_OR_W_DIMENSION
					: D3D_FL9_3_REQ_TEXTURE2D_U_OR_V_DIMENSION;
				break;

			default: // D3D_FEATURE_LEVEL_10_0 & D3D_FEATURE_LEVEL_10_1
				maxsize = (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE3D)
					? D3D10_REQ_TEXTURE3D_U_V_OR_W_DIMENSION
					: D3D10_REQ_TEXTURE2D_U_OR_V_DIMENSION;
				break;
		}

		if (!FillInitData(width, height, depth, mipCount, arraySize, format, maxsize, bitSize, bitData, twidth, theight, tdepth, skipMip, initData.get())) return false;

		hr = CreateD3DResources(d3dDevice, resDim, twidth, theight, tdepth, mipCount - skipMip, arraySize, format, isCubeMap, initData.get(), texture, textureView);
	}

	return hr == S_OK;
}

//--------------------------------------------------------------------------------------
TBOOL CreateDDSTextureFromMemory(
	_In_ ID3D11Device* d3dDevice,
	_In_reads_bytes_(ddsDataSize) const byte* ddsData,
	_In_ size_t ddsDataSize,
	_Out_opt_ ID3D11Resource** texture,
	_Out_opt_ ID3D11ShaderResourceView** textureView,
	_In_ size_t maxsize
	)
{
	if (!d3dDevice || !ddsData || (!texture && !textureView))  return false;

	// Validate DDS file in memory
	if (ddsDataSize < (sizeof(TU32) + sizeof(DDS_HEADER)))  return false;

	TU32 dwMagicNumber = *(const TU32*)(ddsData);
	if (dwMagicNumber != DDS_MAGIC) return false;

	const DDS_HEADER* header = reinterpret_cast<const DDS_HEADER*>(ddsData + sizeof(TU32));

	// Verify header to validate DDS file
	if (header->size != sizeof(DDS_HEADER) ||
		header->ddspf.size != sizeof(DDS_PIXELFORMAT)) return false;

	// Check for DX10 extension
	bool bDXT10Header = false;
	if ((header->ddspf.flags & DDS_FOURCC) &&
		(MAKEFOURCC('D', 'X', '1', '0') == header->ddspf.fourCC))
	{
		// Must be long enough for both headers and magic value
		if (ddsDataSize < (sizeof(DDS_HEADER) + sizeof(TU32) + sizeof(DDS_HEADER_DXT10))) return false;

		bDXT10Header = true;
	}

	ptrdiff_t offset = sizeof(TU32) + sizeof(DDS_HEADER) + (bDXT10Header ? sizeof(DDS_HEADER_DXT10) : 0);

	return CreateTextureFromDDS(d3dDevice, header, ddsData + offset, ddsDataSize - offset, texture, textureView, maxsize);	
}

#endif